Stormwater treatment using permeable pavements

Abstract

Permeable pavements are generally used in water-sensitive urban design as a component of a treatment train and as a source control measure for reducing stormwater flows and pollutant loads. In Australia, permeable pavement systems are an emerging technology and consequently there are few installations more than 10 years old. The performance of permeable pavements in terms of treatment of urban stormwater runoff from a number of typical, but different urban catchments is discussed. Water quality monitoring was carried out in the field to quantify the improvement that permeable pavement systems can make to runoff quality at a car park located at North Haven in Adelaide, South Australia, that utilise both conventional and permeable pavement systems. Extensive laboratory analysis using stormwater collected from four sites was carried out to assess the effectiveness of permeable pavement systems for reducing pollutant discharges. In general, the permeable pavement systems were found to improve stormwater quality when tested at a 5% significance level. The results show that, on average, permeable pavements were able to reduce nutrient concentrations (total nitrogen and total phosphorus), heavy metals (zinc, lead, copper, cadmium and nickel) and total suspended solids. The reductions in pollutant concentrations can be mainly attributed to mechanical filtration by various components of the permeable pavement system.

The sources, impact and management of car park runoff pollution: A review

“…Legret and Colandini (1999) have specifically focussed on the behaviour of metals and by applying a mass balance scenario to a porous asphalt structure draining a street surface have determined that pollutant retention was mainly in the porous surface accounting for 89% of the incoming Pb but only 43%, 15% and 34% for Cu, Cd and Zn respectively. However, apart from Zn, these metal removal performances were considerably better than Beecham et al (2012) have reported for a car park draining through a permeable pavement structure (Cu, 3%; Ni, 18%; Pb, 9%; Zn, 38%). Collins et al (2008Collins et al ( , 2010 compared the hydrologic and nitrogen species removal of four types of permeable pavement (pervious concrete; interlocking pavers with small sized aggregate in the joints [12.9% and 8.5% open surface area]; concrete grid pavers filled with sand) with a standard asphalt surface in a 1 year old parking lot.…”

“…Boving et al (2008) highlighted that sand imported by cars to parking areas during winter conditions is a principal cause of clogging. The contamination of underlying soil and groundwater is a potential problem, particularly in car parks where high levels of soluble pollutants may occur (Beecham et al, 2012) and the installation of an impermeable membrane is recommended in such situations (Scholz and Grabowiecki, 2007). Concerns about the effectiveness of porous pavements in controlling stormwater runoff on clay soils was specifically tested by Dreelin et al (2006) who demonstrated a 93% runoff reduction for a plastic matrix filled with sand and planted with grass over a gravel base compared with a conventional asphalt surface.…”

“…Brown et al (2009) reported that permeable pavements constructed as either porous asphalt or open-jointed paving blocks achieved an excellent removal of suspended solids (90-96%) as well as performing a 'sieving action' in which coarser solids were preferentially retained at the geotextile interface. Given these efficient removal performances it is surprising that Beecham et al (2012) only recorded a 38% reduction in the average concentration of TSS for a permeable pavement structure receiving car park drainage. Pratt et al (1999) investigated the potential for the underground free draining structure to act as an aerobic digester supporting the microbial degradation of oils removed from the car park surface.…”

Editorial

“…Specifically, the authors consider the laboratory-scale effectiveness of hydrous ferric oxide in the removal of heavy metals when subjected to intermittent loading. Results were positive and, similar to Beecham et al (2012) will be of interest and value to the practising water manager and academics alike.…”

“…In the first of the two papers, Beecham et al (2012) present valuable data on the extent to which pollutant removal occurs in a permeable pavement system compared to a conventional pavement when treating rainfall runoff of varying quality. Although permeable pavement technology has been with us for 20 years, the uptake has been limited and sporadic.…”